1. Field of the Invention
The present invention relates to weather-resistant exterior construction materials, and more particularly to roofing and shingle products.
2. Brief Description of the Prior Art
Roofing products formed from laminated multiple layers of shingle material are well known. For example, roofing shingles in which a base shingle is overlaid with one or more sections of shingle material to provide a decorative three-dimensional effect are known. In these shingles, both the base and the overlaid section include a reinforcing web formed, for example, from glass fiber, and the base and overlaid sections are laminated together. A well-defined three-dimensional appearance can be provided through selection of the geometry of the over-laid sections, the placement of the overlaid sections on the base shingle, and the scheme by which the roof is to be covered with the shingles. However, an important aspect contributing to the ultimate three-dimensional appearance of the roof covering is a sharp discontinuity at the edges of the overlaid sections. This type of shingle can be easily made: The sections can be simply cut from the same material as the base shingles, and the cut sections can be subsequently laminated on the base shingle. On the other hand, the double layering of reinforcing web which results from this assembly contributes to the weight and decreases the flexibility of the shingles. An alternative is to simply overlay one or more sections of asphaltic coating material on top of a base shingle made up of an asphalt-coated reinforcing web in which mineral surfacing material has already been embedded, with additional mineral surfacing material being subsequently embedded in the overlay. While an attractive three-dimensional appearance can be achieved with this alternative, the shingle produced may be substantially thicker through the overlaid sections than through the base shingle, which may decrease the flexibility of the product in comparison with the base shingle. The decreased flexibility may make the overlaid shingle more difficult to install on roof hips and in roof ridges, where the shingle must be bent substantially to conform to the roof surface.